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Shared Version Number Across All Projects In A Solution

Backstory: We have a terminal app that uses WCF services and an MVC web back-end. We want to show the version # of the terminal on the MVC page.

To do this, first create a SharedAssemblyInfo.cs in a solution folder, or in your main project file. It will contain no more than the following text:

// Solution version

using System.Reflection;
[assembly: AssemblyVersion(“0.1.1.6”)]
[assembly: AssemblyFileVersion(“0.1.1.6”)]

For each project that will be sharing this file,
(a) go to the /Properties/AssemblyInfo.cs file and comment out the version # stuff.
(b) Add an existing file to the project. Find the SharedAssemblyInfo.cs and click the dropdown next to “Add” and select “Add as link”.

Done!

If you are displaying a version number in your web project and System.Reflection.Assembly.GetExecutingAssembly() returns null, you need to use GetEntryAssembly().

If you find that the version # always returns 0.0.0.0 when using (System.Reflection.Assembly.GetexecutingAssembly() ?? System.Reflection.Assembly.GetEntryAssembly()).GetName().Version.ToString(), then get a type that is outside your Assembly (I have a Common project consumed by all assemblies) and get its version # from that, like this:

typeof(Some.Type.Outside.of.Web.Assembly).Assembly.GetName().Version.ToString()

Hope this helps!

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Updating an object with MVC

When editing an object (like an entity) in MVC, it returns a new one populated with your objects. If you try to save it using dataContext.Attach(), you may find that when saving it bombs on you. A great example of this would be something like a DateTime called .CreatedOn, since you wouldn’t let users edit it, would be the same value as new DateTime() which is year 0 or 1. When the object attempts to be persisted it won’t allow a date that low to be stored in a normal datetime field in SQL (datetime2, yes, but datetime should be sufficient in most cases) and bombs with a YSOD.

Maybe there’s a better way, but until I discover it or someone points it out to me, here’s what I did:

/// <summary>
/// Maps only the submitted changes in model state from one object to another.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="mapToObject"></param>
/// <param name="mapFromObject"></param>
public static void MapChangedProperties<T>(this ModelStateDictionary modelState, ref T mapToObject, T mapFromObject)
{
	var props = typeof(T).GetProperties();
	foreach (var item in modelState)
	{
		var prop = props.FirstOrDefault(p => p.Name == item.Key);
		if (prop != null)
		{
			prop.SetValue(mapToObject, prop.GetValue(mapFromObject, null), null);
		}
	}
}

To use, get the object out of the database and run this on it:

// "obj" is our returned model name, and we have a database connection open
if (ModelState.IsValid)
{
        dbObj = db.Objs.Single(o => o.ID = obj.ID);
        ModelState.MapChangedProperties(ref dbObj, obj);
        dbObj.ModifiedDT = DateTime.UtcNow;
        db.SaveChanges();
}
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Linq to SQL, Linq to EF, DateTime.Now and GETDATE() Woes

A client of ours requires that each one of their cruise ships have different timezones they exist in. When they create gaming records for their ships, the records created have to fall in their timezone in order for the game to close at the right time. They called us up today and mentioned that the games were closing an hour early for a particular set of ships.

That’s the backstory, what was found was that a Linq to EF query with DateTime.Now in it gets converted to GETDATE() in the expression tree, while L2S does not.

The example here EFDataStore.GetActiveGamesByDateTime(DateTime.Now) would be converted to SELECT * FROM Games WHERE CloseTime >= GETDATE(), and on the DB server, daylight savings time cannot be disabled, and on the app server, DST is turned off.

Changing the C# code to this solved the problem:

DateTime dt = DateTime.Now;

EFDataStore.GetActiveGamesByDateTime(dt)

When EF walks the expression tree using reflection, it won’t see DateTime.Now in there and won’t convert it to GETDATE(), but it will use the actual date and time stored in the variable.

We never had problems with other ships because the servers that run these particular ships have a separate database server than the application server, where the other ships have application and DB servers on a single box.

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Conditionally show the expand/collapse button (+/-) dependent on an expression

I’m working on a report where some of the rows have drilldowns and some do not. The boss wanted only the rows with drilldowns to have the expander next to them. I didn’t think it was possible but he was able to guide me in the right direction, so here is how it is done.

Normally, you would have your group or details’ visibility toggled by another report item (a textbox in almost all cases). The textbox is whatever item you want the expander to appear next to. There is no built-in expression to toggle the visibility of the expander itself, so to conditionally hide or show the expander:

  1. Add an empty column to the left of where the expander would normally appear. Size it down so it’s not too big (too small and the expander won’t appear at all). This column is not bound to any data so it will be blank all the time.
  2. Right click your detail group you want hidden or shown and click Properties. Click the Visibility tab. Change the textbox so it’s the new blank column instead of the one to the right of it. Click OK to close the dialog.
  3. Run the report so you can be sure the expander appears. If the field is sized too thin, the expander won’t appear, so be sure you do this before the next step.
  4. Right click the empty cell where the expander is shown and click Properties. Click the Visibility tab. Under Initial Visibility, select Expression and enter the expression to use to hide or show that expander (+/-) control.

Now, the expander control itself is controlled by that expression you entered in step 4. Super easy to do and nice outside-the-box thinking to make it work. Thanks boss!

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ClickOnce deployments to a networked drive

Learned something new. I could not deploy a WPF application using ClickOnce using a mapped network drive. It kept coming back at me saying that “The path does not exist.”, even though I copied the path from Windows Explorer directly into the ClickOnce deployment dialog.

The problem was that I had VS2010 starting using administrator credentials – and there was no way to allow access to that shared drive that initially requires a username and password to access. Starting VS not using admin credentials fixed the problem.

Hope this helps someone else out there, as I was stumped for a bit on this one.

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Monotouch Deserialization FormatException “Input string was not in the correct format” – Solved

Ran into an interesting issue with some POCO entities being passed from my VS2010 WCF service to my Monotouch client. Here’s an example of how you cannot always trust the error message that is given to you.

I’m passing down an object graph, with a container object that contains an array of events and an array of People objects, each containing a Dictionary of event IDs and times. (Why nullable int as the key? Monotouch has issues with value types as dictionary keys, see Xamarin’s list of limitations.) The event IDs contained in there map to the events sent in the container object. Some of the people passed down may not have attended the event at all, meaning that aforementioned dictionary was empty. When I was getting the “Input string was not in the correct format” error, I thought that Monotouch WCF was bombing on a nullable int on the person being null, which didn’t make sense since I was pulling down the same person object in a different call that had nullable ints and everything worked peachy. Come to find out, it was the empty Dictionary causing the problem. In my service code, before passing the object back to the client, I loop through and null out any empty dictionaries in my object graph.

Hope this helps someone out there.

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Monotouch.Dialog – Nullable Date and Nullable Date/Time Elements

http://stackoverflow.com/questions/10199084/monotouch-dialog-dateelement-that-accepts-a-null-value-as-input/10212471#10212471 .

I rolled my own nullable date/time and date-only pickers for Monotouch.Dialog out of necessity.

I’m curious to see if someone can make the picker pop up like an actionsheet on the current view rather than entering into another view controller… it would look more professional and be in line with the rest of Apple’s UI. Anyone care to take a stab at doing this?

You can see my source code at the StackOverflow link.

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IE9 and Silverlight caching problems

I ran into a problem with customers not able to retrieve a new copy of a silverlight app using IE. I took over a user’s session remotely to witness this myself. I pressed F5 and Ctrl-F5 (hard refresh) and while the HTML page hard-refreshed, the XAP file refused to load until I deleted the customer’s IE cache and reloaded it. Why IE refused to honor the hard refresh, I will never know; but one thing is for certain, and that is you can NEVER trust the caching policies of the browser completely.

I found this link http://codeblog.larsholm.net/2010/02/avoid-incorrect-caching-of-silverlight-xap-file/ describing how to fix this issue. In the OBJECT tag that hosts the SL app in your HTML page, you append to the end of the XAP file url the last file modification date/time. This way, the XAP file will only reload if the file changes. I had to make some modifications to the code I got from the aforementioned URL to make it work properly.

So, instead of:

<param name="source" value="ClientBin/SilverlightApp.xap"/>

You want to put in its place:

<%
string orgSourceValue = @"~/ClientBin/SilverlightApplication.xap"; // path to and name of your XAP file
string param;
if (System.Diagnostics.Debugger.IsAttached)
{
param = "<param name=\"source\" value=\"" + orgSourceValue + "\" />";
}
else
{
string xappath = HttpContext.Current.Server.MapPath(orgSourceValue);
DateTime xapCreationDate = System.IO.File.GetLastWriteTime(xappath);
param = "<param name=\"source\" value=\"" + orgSourceValue.TrimStart('~') + "?ignore=" + xapCreationDate.ToString("yyyymmddhhmmss") + "\" />";
}
Response.Write(param);
%>

This way, if you are debugging your application, the path remains the same, but if there is no debugger attached, then the file is cached as long as the file modification date does not change.

I made the following changes from the original poster’s code:

  • The output of the time was a simple .ToString() which did not form a valid URL. This has been changed into more of a timestamp, where all non-numeric values were removed.
  • How the path to the XAP file was stored has been changed. Since we’re working from the base dir out, I used the .Net style of server paths, prepending the tilde (~) and then when writing it out, removing the tilde from the start of the path.
I will also add that the “ignore?” portion can really be anything you want it to be. As long as the URL does not change, the application will be cached by browsers that are set up to support caching. Once you upload a new copy of your XAP file, the file modification date will change, and then the URL changes, thus forcing browsers to get a new copy of your app.

Hope this helps someone out there.

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Auto-Updating TextBlock for Silverlight

This textblock usercontrol updates its contents every second. Just set a binding to the text property and voila!

Note that the part inside the Dispatcher BeginInvoke method that gets the binding expression and sets the binding to the parent binding of the binding expression is equivalent to the missing .UpdateTarget() found in WPF.

XAML

<UserControl x:Class="CLARIA.Infrastructure.SL.RichClient.Controls.UpdatingTextBlock"
		xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
		xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
		xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
		xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
		mc:Ignorable="d"
		d:DesignHeight="28" d:DesignWidth="240">
	<TextBlock Name="text" />
</UserControl>

C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using System.Threading;
using System.Windows.Data;
using System.ComponentModel;

namespace CLARIA.Infrastructure.SL.RichClient.Controls
{
public partial class UpdatingTextBlock : UserControl, IDisposable
{
public UpdatingTextBlock()
{
InitializeComponent();

// Set timer
if (!DesignerProperties.GetIsInDesignMode(this))
{
t = new Timer(new TimerCallback(TimerCallbackMethod), null, 0, 1000);
}
}

Timer t;
BindingExpression exp;

public string Text
{
get { return (string)GetValue(TextProperty); }
set { SetValue(TextProperty, value); }
}

// Using a DependencyProperty as the backing store for Text. This enables animation, styling, binding, etc…
public static readonly DependencyProperty TextProperty =
DependencyProperty.Register(“Text”, typeof(string), typeof(UpdatingTextBlock), new PropertyMetadata(“”));

void TimerCallbackMethod(object target)
{
Dispatcher.BeginInvoke(() =>
{
if (exp == null)
{
exp = GetBindingExpression(UpdatingTextBlock.TextProperty);
}
if (exp != null)
{
SetBinding(UpdatingTextBlock.TextProperty, exp.ParentBinding);
}
text.Text = this.Text;
});
}

~UpdatingTextBlock()
{
Dispose();
}

#region IDisposable Members

bool _disposed = false;

public void Dispose()
{
if (!_disposed)
{
if (t != null)
t.Dispose();
_disposed = true;
}
}

#endregion
}
}